This invention relates to cutters for rubber samples, and to cutting machines having toggle mechanisms for reciprocal motion of a cutting die.
In the operation of rheometers or curemeters for evaluating the physical behavior of rubber compounds during the process of vulcanization, it has been found helpful for obtaining repeatability to charge the rheometer or curemeter with samples which are of consistent volume. The sample volume should be just slightly more than that required to fill the cavity of the testing device. If the sample volume is insufficient to fill the cavity, cavity pressure is inadequate and erroneous values will result. If the sample volume is significantly too large, an excess of rubber will be squeezed out of the cavity during the initial stages of the test, retarding sample heating and causing erratic results and also necessitating excessive cleaning effort. Thus, a device which could produce an accurate, constant volume of sample would be of value in maintaining testing accuracy and speed, especially in a quality control application, where samples are continually tested to monitor production operations.
It is an object of the present invention to provide a reliable, quick and relatively simple mechanical cutter which will produce constant-volume samples of rubber compound. It is another object of this invention to provide a method for cutting samples of rubber compound by first sizing, then cutting a portion of rubber compound to a constant volume.